Edge-aware intra prediction for depth-map coding

This work proposes a new intra prediction coding scheme for depth map images used in view interpolation. The main goal is to design a prediction scheme which can reduce the prediction error energy in blocks with arbitrary edge shapes. This will reduce the rate needed to encode such blocks while also eliminating some of the annoying artifacts caused by quantization. Since depth maps typically consist of smooth regions separated by edges, we find it sufficient to design prediction schemes which can make effective use of edge information. Working from the intra prediction framework in H.264, we provide a graph representation of pixels in a block and pixels from previously coded blocks and construct an edge-aware prediction scheme based on this. We also employ existing rate-distortion (RD) optimization methods to further improve the coding performance. Our proposed methods reduce the bit rate for depth maps by up to 29% for a fixed interpolated PSNR for some sequences.